
#ifndef GRAPHICSWINDOW_H
#define GRAPHICSWINDOW_H

#include <windows.h>

HDC			hDC;		// Private GDI Device Context
HGLRC		hRC;		// Permanent Rendering Context
HWND		hWnd;		// Holds Our Window Handle
HINSTANCE	hInstance;	// Holds The Instance Of The Application

int height;
int width;
bool active;
bool fullscreen;
bool quitKey;

void (*drawFunc)(void);
void (*resizeFunc)(int,int);

LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

int initWindow(char* title, int width, int height, bool fullscreen);
void quitWindow();	
BOOL createWindow(char* title, int width, int height, int bits, bool fullscreenflag);
void killWindow();


void setWindowResizeFunc(void (*func)(int,int)) { resizeFunc = func; }
void setWindowDrawFunc(void (*func)(void)) { drawFunc = func; }


///////////////////////////////////////////////////////////////////////////////////////////
void quitWindow() { quitKey = true; }



///////////////////////////////////////////////////////////////////////////////////////////
void killWindow() {

	if ( fullscreen ) {
		ChangeDisplaySettings(NULL,0);					// If So Switch Back To The Desktop
		ShowCursor(TRUE);								// Show Mouse Pointer
	}

	if (hRC) {											// Do We Have A Rendering Context?
		if (!wglMakeCurrent(NULL,NULL)) {				// Are We Able To Release The DC And RC Contexts?
			MessageBox(NULL,"Release Of DC And RC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		}
		if (!wglDeleteContext(hRC))	{					// Are We Able To Delete The RC?
			MessageBox(NULL,"Release Rendering Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		}
		hRC=NULL;										// Set RC To NULL
	}

	if (hDC && !ReleaseDC(hWnd,hDC)) {					// Are We Able To Release The DC
		MessageBox(NULL,"Release Device Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hDC=NULL;										// Set DC To NULL
	}

	if (hWnd && !DestroyWindow(hWnd)) {					// Are We Able To Destroy The Window?
		MessageBox(NULL,"Could Not Release hWnd.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hWnd=NULL;										// Set hWnd To NULL
	}

	if (!UnregisterClass("OpenGL",hInstance)) {			// Are We Able To Unregister Class
		MessageBox(NULL,"Could Not Unregister Class.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hInstance=NULL;									// Set hInstance To NULL
	}
}



///////////////////////////////////////////////////////////////////////////////////////////
/*	This Code Creates Our OpenGL Window.  Parameters Are:					*
 *	title			- Title To Appear At The Top Of The Window				*
 *	width			- Width Of The GL Window Or Fullscreen Mode				*
 *	height			- Height Of The GL Window Or Fullscreen Mode			*
 *	bits			- Number Of Bits To Use For Color (8/16/24/32)			*
 *	fullscreenflag	- Use Fullscreen Mode (TRUE) Or Windowed Mode (FALSE)	*/
BOOL createWindow(char* title, int width, int height, int bits, bool fullscreenflag) {
	unsigned int PixelFormat;			// Holds The Results After Searching For A Match
	WNDCLASS	wc;						// Windows Class Structure
	DWORD		dwExStyle;				// Window Extended Style
	DWORD		dwStyle;				// Window Style
	RECT		WindowRect;				// Grabs Rectangle Upper Left / Lower Right Values
	WindowRect.left=(long)0;			// Set Left Value To 0
	WindowRect.right=(long)width;		// Set Right Value To Requested Width
	WindowRect.top=(long)0;				// Set Top Value To 0
	WindowRect.bottom=(long)height;		// Set Bottom Value To Requested Height

	fullscreen = fullscreenflag;			// Set The Global Fullscreen Flag

	hInstance			= GetModuleHandle(NULL);				// Grab An Instance For Our Window
	wc.style			= CS_HREDRAW | CS_VREDRAW | CS_OWNDC;	// Redraw On Size, And Own DC For Window.
	wc.lpfnWndProc		= (WNDPROC)WndProc;						// WndProc Handles Messages
	wc.cbClsExtra		= 0;									// No Extra Window Data
	wc.cbWndExtra		= 0;									// No Extra Window Data
	wc.hInstance		= hInstance;							// Set The Instance
	wc.hIcon			= LoadIcon(NULL, IDI_WINLOGO);			// Load The Default Icon
	wc.hCursor			= LoadCursor(NULL, IDC_ARROW);			// Load The Arrow Pointer
	wc.hbrBackground	= NULL;									// No Background Required For GL
	wc.lpszMenuName		= NULL;									// We Don't Want A Menu
	wc.lpszClassName	= "OpenGL";								// Set The Class Name

	if (!RegisterClass(&wc)) {									// Attempt To Register The Window Class
		MessageBox(NULL,"Failed To Register The Window Class.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;											// Return FALSE
	}
	
	if (fullscreen)	{											// Attempt Fullscreen Mode?
		DEVMODE dmScreenSettings;								// Device Mode
		memset(&dmScreenSettings,0,sizeof(dmScreenSettings));	// Makes Sure Memory's Cleared
		dmScreenSettings.dmSize=sizeof(dmScreenSettings);		// Size Of The Devmode Structure
		dmScreenSettings.dmPelsWidth	= width;				// Selected Screen Width
		dmScreenSettings.dmPelsHeight	= height;				// Selected Screen Height
		dmScreenSettings.dmBitsPerPel	= bits;					// Selected Bits Per Pixel
		dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;

		// Try To Set Selected Mode And Get Results.  NOTE: CDS_FULLSCREEN Gets Rid Of Start Bar.
		if (ChangeDisplaySettings(&dmScreenSettings,CDS_FULLSCREEN)!=DISP_CHANGE_SUCCESSFUL) {

			// If The Mode Fails, Offer Two Options.  Quit Or Use Windowed Mode.
			if (MessageBox(NULL,"The Requested Fullscreen Mode Is Not Supported By\nYour Video Card. Use Windowed Mode Instead?","NeHe GL",MB_YESNO|MB_ICONEXCLAMATION)==IDYES) {
				fullscreen=FALSE;		// Windowed Mode Selected.  Fullscreen = FALSE
			}
			else {
				// Pop Up A Message Box Letting User Know The Program Is Closing.
				MessageBox(NULL,"Program Will Now Close.","ERROR",MB_OK|MB_ICONSTOP);
				return FALSE;									// Return FALSE
			}
		}
	}

	if (fullscreen) {											// Are We Still In Fullscreen Mode?
		dwExStyle=WS_EX_APPWINDOW;								// Window Extended Style
		dwStyle=WS_POPUP;										// Windows Style
		ShowCursor(FALSE);										// Hide Mouse Pointer
	}
	else {
		dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;			// Window Extended Style
		dwStyle=WS_OVERLAPPEDWINDOW;							// Windows Style
	}

	AdjustWindowRectEx(&WindowRect, dwStyle, FALSE, dwExStyle);		// Adjust Window To True Requested Size

	// Create The Window
	if (!(hWnd=CreateWindowEx(	dwExStyle,							// Extended Style For The Window
								"OpenGL",							// Class Name
								title,								// Window Title
								dwStyle |							// Defined Window Style
								WS_CLIPSIBLINGS |					// Required Window Style
								WS_CLIPCHILDREN,					// Required Window Style
								0, 0,								// Window Position
								WindowRect.right-WindowRect.left,	// Calculate Window Width
								WindowRect.bottom-WindowRect.top,	// Calculate Window Height
								NULL,								// No Parent Window
								NULL,								// No Menu
								hInstance,							// Instance
								NULL)))								// Dont Pass Anything To WM_CREATE
	{
		killWindow();								// Reset The Display
		MessageBox(NULL,"Window Creation Error.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	static	PIXELFORMATDESCRIPTOR pfd=				// pfd Tells Windows How We Want Things To Be
	{
		sizeof(PIXELFORMATDESCRIPTOR),				// Size Of This Pixel Format Descriptor
		1,											// Version Number
		PFD_DRAW_TO_WINDOW |						// Format Must Support Window
		PFD_SUPPORT_OPENGL |						// Format Must Support OpenGL
		PFD_DOUBLEBUFFER,							// Must Support Double Buffering
		PFD_TYPE_RGBA,								// Request An RGBA Format
		bits,										// Select Our Color Depth
		0, 0, 0, 0, 0, 0,							// Color Bits Ignored
		0,											// No Alpha Buffer
		0,											// Shift Bit Ignored
		0,											// No Accumulation Buffer
		0, 0, 0, 0,									// Accumulation Bits Ignored
		16,											// 16Bit Z-Buffer (Depth Buffer)  
		0,											// No Stencil Buffer
		0,											// No Auxiliary Buffer
		PFD_MAIN_PLANE,								// Main Drawing Layer
		0,											// Reserved
		0, 0, 0										// Layer Masks Ignored
	};
	
	if (!(hDC=GetDC(hWnd)))	{ 						// Did We Get A Device Context?
		killWindow();								// Reset The Display
		MessageBox(NULL,"Can't Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	if (!(PixelFormat=ChoosePixelFormat(hDC,&pfd))){// Did Windows Find A Matching Pixel Format?
		killWindow();								// Reset The Display
		MessageBox(NULL,"Can't Find A Suitable PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	if(!SetPixelFormat(hDC,PixelFormat,&pfd)) {		// Are We Able To Set The Pixel Format?
		killWindow();								// Reset The Display
		MessageBox(NULL,"Can't Set The PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	if (!(hRC=wglCreateContext(hDC))) {				// Are We Able To Get A Rendering Context?
		killWindow();								// Reset The Display
		MessageBox(NULL,"Can't Create A GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	if(!wglMakeCurrent(hDC,hRC)) {					// Try To Activate The Rendering Context
		killWindow();								// Reset The Display
		MessageBox(NULL,"Can't Activate The GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	ShowWindow(hWnd,SW_SHOW);						// Show The Window
	SetForegroundWindow(hWnd);						// Slightly Higher Priority
	SetFocus(hWnd);									// Sets Keyboard Focus To The Window
	resizeFunc(width, height);					// Set Up Our Perspective GL Screen

	return TRUE;									// Success
}



///////////////////////////////////////////////////////////////////////////////////////////
LRESULT CALLBACK WndProc(	
							HWND	hWnd,			// Handle For This Window
							UINT	uMsg,			// Message For This Window
							WPARAM	wParam,			// Additional Message Information
							LPARAM	lParam)			// Additional Message Information
{
	switch (uMsg) {									// Check For Windows Messages
	
		case WM_ACTIVATE:							// Watch For Window Activate Message
			if (!HIWORD(wParam)) {					// Check Minimization State
				active = true;		// Program Is Active
			}
			else {
				active = false;		// Program Is No Longer Active
			}
			return 0;								// Return To The Message Loop

		case WM_SYSCOMMAND:							// Intercept System Commands
			switch (wParam)	{						// Check System Calls
				case SC_SCREENSAVE:					// Screensaver Trying To Start?
				case SC_MONITORPOWER:				// Monitor Trying To Enter Powersave?
				return 0;							// Prevent From Happening
			}
			break;									// Exit

		case WM_CLOSE:								// Did We Receive A Close Message?
			PostQuitMessage(0);						// Send A Quit Message
			return 0;								// Jump Back

		case WM_SIZE:								// Resize The OpenGL Window
			resizeFunc(LOWORD(lParam),HIWORD(lParam));  // LoWord=Width, HiWord=Height
			return 0;								// Jump Back
	}

	// Pass All Unhandled Messages To DefWindowProc
	return DefWindowProc(hWnd,uMsg,wParam,lParam);
}



///////////////////////////////////////////////////////////////////////////////////////////
int initWindow(char* title, int width, int height, bool fullscreen) {
	
	MSG	msg;
	bool done = false;
	
	hDC = NULL;		// Private GDI Device Context
	hRC = NULL;		// Permanent Rendering Context
	hWnd = NULL;	// Holds Our Window Handle

	if ( !createWindow(title, width, height, 16, fullscreen) ) {
		return 0;
	}

	while ( !done ) {

		// Is There A Message Waiting?
		if ( PeekMessage(&msg,NULL,0,0,PM_REMOVE) ) {

			if ( msg.message == WM_QUIT ) {	done = true; }
			else {
				TranslateMessage(&msg);
				DispatchMessage(&msg);
			}
		}
		else {
			drawFunc();
			//if ( active || quitKey ) { done = true; }
			//else { 
				SwapBuffers(hDC); 
			//}
		}

	}

	killWindow();
	return (int)(msg.wParam);
}

#endif